Behavioral evidence indicates that the neuropeptide nociceptin/orphaninFQ (NOC) attenuates ethanol intake and relapse associated with ethanol exposure and stressful events. Because the central nucleus of the amygdala (CeA) plays a crucial role in ethanol dependence, we speculate that the anti-alcohol and anti-stress properties of NOC are mediated via its interactions with the GABA and corticotropin-releasing factor (CRF) systems within the CeA. Our research is centered on the effects of acute and chronic ethanol on CeA neurons. We demonstrated that acute ethanol increases GABA transmission in CeA of both na[unreadable]ve and ethanol-dependent rats by increasing GABA release, and that this ethanol effect involves intermediary substrates such as presynaptic CRF1 receptors. We recently reported that NOC decreases GABAergic transmission and release and prevents the ethanol-induced enhancement of GABAergic transmission in CeA. Our preliminary studies indicate that NOC opposes the actions of CRF, and that neuroadaptations such as increased sensitivity of the NOC system occur during the development of ethanol dependence in CeA. So far the mechanism of NOC action is unknown, and the interactions of the NOC and CRF systems likely to take place to regulate the synaptic effects of ethanol have not been investigated. Based on these combined findings, in this research proposal we will use electrophysiological, molecular biological and in vivo microdialysis approaches to study the antagonistic role of NOC in the ethanol effects on GABAergic transmission in CeA and the molecular mechanisms that mediate such NOC effects (Aims 1 and 2). We also intend to uncover the neuroadaptive response(s) of the NOC system associated with ethanol dependence (Aims 1 and 2). In Aim 3, we will test our hypothesis that NOC opposes CRF effects at a presynaptic site, and we will identify the interactions of NOC and CRF on GABAergic synapses in CeA. Emphasis will be given to determine the neuroadaptations that take place between the NOC and CRF systems in association with ethanol-dependence. A better understanding of the neuroadaptations shaping the synaptic networks involved in ethanol-dependence represents a challenge to alcohol researchers and will be useful toward the uncovering of new therapeutic agents to alleviate alcohol dependence. PUBLIC HEATLH RELEVANCE: Recent behavioral studies have revealed a modulatory effect of the neuropeptide nociceptin on ethanol- and stress-related phenomena, suggesting an important role of nociceptin in ethanol dependence. However, until now there have been no physiological data on the possible interactions of nociceptin and ethanol at the synaptic level. Therefore, the experiments proposed in this application will use electrophysiological, molecular biological and in vivo microdialysis approaches to study for the first time the cellular interactions of nociceptin, ethanol and corticotropin-releasing factor (CRF) systems at GABAergic synapses in the central nucleus of the amygdala, a brain region highly implicated in alcohol dependence. Emphasis will be given to determining the neuroadaptations that take place between the nociceptin and CRF systems in association with ethanol dependence. A better understanding of the neuroadaptations shaping the synaptic networks involved in ethanol dependence will be useful toward revealing new therapeutic agents to alleviate alcohol dependence.